| 1. |
- Buck, Dietrich, 1990-, et al.
(författare)
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Production and In-Plane Compression Mechanics of Alternatively Angled Layered Cross-Laminated Timber
- 2018
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Ingår i: BioResources. - : University of North Carolina Press. - 1930-2126 .- 1930-2126. ; 13:2, s. 4029-4045
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Tidskriftsartikel (refereegranskat)abstract
- Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. This paper reports mechanical properties of cross-laminated timber (CLT) panels constructed with layers angled in an alternative configuration on a modified industrial CLT production line. Timber lamellae were adhesively bonded together in a single-step press procedure to form CLT panels. Transverse layers were laid at an angle of 45°, instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle. Tests were carried out on 20 five-layered CLT panels divided into two matched groups with either a 45° or a 90° configuration; an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. These tests showed that the 45°-configured panels had a 30% higher compression stiffness and a 15% higher compression strength than the 90° configuration. The results also revealed that the 45°-configured CLT can be industrially produced without using more material than is required for conventional CLT 90° panels. In addition, the design possibility that the 45°-configured CLT can carry a given load while using less material also suggests that it is possible to use CLT in a wider range of structural applications.
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| 2. |
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| 3. |
- Jakobsson, Simon, et al.
(författare)
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How does roadside vegetation management affect the diversity of vascular plants and invertebrates? A systematic review
- 2018
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Ingår i: Environmental Evidence. - : Springer Science and Business Media LLC. - 2047-2382. ; 7:1
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Forskningsöversikt (refereegranskat)abstract
- Background: With appropriate management, based on vegetation removal that reverses late-successional vegetation stages, roadsides can support high levels of biodiversity. However, current recommendations for roadside management to conserve or restore biodiversity are largely based on research on non-roadside grassland habitats, and much of the evidence on how roadside management practices affect biodiversity is found in non-peer-reviewed grey literature. Therefore, based on suggestions from key stakeholders and an initial systematic map that identified 97 studies on how biodiversity is affected by vegetation removal on roadsides, we conducted a full systematic review of the effects on plant and invertebrate diversity of disturbance-based maintenance of roadsides. Methods: The review was restricted to effects of non-chemical interventions such as mowing, burning, grazing and mechanical shrub removal. Studies were selected from the systematic map and from an updated search for more recent literature using a priori eligibility criteria. Relevant articles were subject to critical appraisal of clarity and susceptibility to bias, and studies with low or unclear validity were excluded from the review. Data on species richness, species diversity and abundance of functional groups were extracted together with metadata on site properties and other potential effect modifiers. Results from the 54 included studies were summarised in a narrative synthesis, and impacts of mowing practices on the total species richness and diversity of plants and on the abundance of forbs, graminoids and woody plants were quantitatively analysed using t tests of study-level effect ratios. Results: Nearly all of the 54 studies included in the review were conducted in Europe (29) or North America (24). The vast majority of studies (48) examined impacts of mowing. Effects on vascular plants were reported in 51 studies, whereas 8 of the studies reported on invertebrates. Quantitative analysis of plant species richness and species diversity showed that mowing effects were dependent on the interplay between mowing frequency and hay removal. Thus, there were no statistically significant overall effects of mowing vs. no mowing, frequency of mowing, timing of mowing or hay removal. However, species richness was higher in roadsides mowed once or twice per year with hay removal than in unmown roadsides, and positively affected by mowing twice compared to once per year. Similar, but less pronounced, effects were found for plant species diversity. In addition, mowing had a negative impact on woody plant abundance, and increased mowing frequency had a negative impact on graminoid abundance. The few studies on invertebrates showed effects that diverged across taxon groups, and there was not enough data for quantitative analysis of these results. Conclusions: The results provide evidence on the effects of mowing on plant species richness. To increase plant species richness, roadsides should be mowed each year, preferably twice per year, and hay should be removed after each cutting. The review also identifies large knowledge gaps concerning roadside management and its effects on biodiversity, especially regarding invertebrates. Hence, this systematic review provides not only a valuable basis for evidence-based management but also guidance for future research on this topic, essential to inform management of road networks for biodiversity conservation.
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| 4. |
- Kettis, Åsa
(författare)
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Kvalitet i högre utbildning och forskning
- 2011
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Ingår i: Det goda universitetet. - Uppsala : Uppsala universitet. - 9789155482077 ; , s. 169-181
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Bokkapitel (populärvet., debatt m.m.)
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| 5. |
- Li, Jingya, 1986, et al.
(författare)
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Power Allocation for Two-Cell Two-User Joint Transmission
- 2012
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Ingår i: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 16:19, s. 1474-1477
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we develop a power allocation scheme for the downlink of a two-cell two-user joint transmission system. The objective is to maximize the sum rate under per-cell power constraints. We study a worst case scenario where the carrier phases between the two base stations are un-synchronized, so that joint transmission must be performed without precoding. The derived power allocation scheme is remarkably simple, i.e., each cell transmits with full power to only one user. Note that joint transmission is still possible, when two cells select the same user for data transmission. Moreover, we prove that, in this scenario, the joint transmission case happens with higher probability when the maximum transmit power is high, or the two users are in the overlapped cell-edge area.
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| 6. |
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| 8. |
- Pellegrino, P., et al.
(författare)
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Separation of vacancy and interstitial depth profiles in proton- and boron-implanted silicon
- 2002
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 186, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- A new experimental method of studying shifts between concentration-versus-depth profiles of vacancy-type and interstitial-type defects in ion-implanted silicon is demonstrated. The concept is based on deep level transient spectroscopy (DLTS) measurements utilizing the filling pulse variation technique. The vacancy profile. represented by the vacancy-oxygen center and the interstitial profile, represented by the substitutional carbon-interstitial carbon pair, are obtained at the same sample temperature by varying the duration of the filling pulse, Thus the two profiles can be recorded with a high relative depth resolution, Point defects have been introduced in low doped float zone n-type silicon by implantation with 6 MeV boron ions and 1.3 MeV protons at room temperature, using low doses. For each implantation condition the peak of the interstitial profile is shown to be displaced by similar to 0.5 mum towards larger depths compared to that of the vacancy profile. This shift is primarily attributed to the preferential forward momentum of recoiling Si atoms, in accordance with theoretical predictions.
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| 9. |
- Perepolkin, Dmytro, et al.
(författare)
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The tenets of indirect inference in Bayesian models
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper extends the application of Bayesian inference to probability distributions defined in terms of its quantile function. We describe the method of *indirect likelihood* to be used in the Bayesian models with sampling distributions which lack an explicit cumulative distribution function. We provide examples and demonstrate the equivalence of the "quantile-based" (indirect) likelihood to the conventional "density-defined" (direct) likelihood. We consider practical aspects of the numerical inversion of quantile function by root-finding required by the indirect likelihood method. In particular, we consider a problem of ensuring the validity of an arbitrary quantile function with the help of Chebyshev polynomials and provide useful tips and implementation of these algorithms in Stan and R. We also extend the same method to propose the definition of an *indirect prior* and discuss the situations where it can be useful.
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| 10. |
- Rumpler, Romain, et al.
(författare)
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An observation of the impact of CoViD-19 recommendation measures monitored through urban noise levels in central Stockholm, Sweden
- 2020
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Ingår i: Sustainable cities and society. - : Elsevier. - 2210-6707. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- Sweden stands out among the other European countries by the degree of restrictive measures taken towards handling the 2019 coronavirus outbreak, associated with the CoViD-19 pandemic. While several governments have imposed a nationwide total or partial lockdown in order to slow down the spread of the virus, the Swedish government has opted for a recommendation-based approach together with a few imposed restrictions. In the present contribution, the impact of this strategy will be observed through the monitored variation of the city noise levels during the associated period. The data used are recorded during a campaign of over a full year of noise level measurements at a building facade situated in a busy urban intersection in central Stockholm, Sweden. The noise level reductions, observed during the period of restrictions, are shown to be comparable to those found for the two most popular public holidays in Sweden with a peak reduction occurring during the first half of April 2020. Contrary to what has been recently discussed in public media, the spread of the virus, the recommendations, and the restrictions imposed during the ongoing pandemic clearly have had a significant effect on the transport and other human-related activities in Stockholm. In this unique investigation, the use of distributed acoustic sensors has thus shown to be a viable solution not only to enforce regulations but also to monitor the effectiveness of their implementation.
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